import sys

for line in sys.stdin:
    if len(line)>1:
        x1, y1, x2, y2 = line.strip('\n').split()
        x1, y1, x2, y2 = float(x1), float(y1), float(x2), float(y2)
        print ((x1-x2)**2+(y1-y2)**2)**0.5 import sys sys for line in sys.stdin:
    if len(line)>1:
        x1, y1, x2, y2 = line.strip('\n').split()
        x1, y1, x2, y2 = float(x1), float(y1), float(x2), float(y2)
        print ((x1-x2)**2+(y1-y2)**2)**0.5 line sys.stdin sys stdin if len(line)>1:
        x1, y1, x2, y2 = line.strip('\n').split()
        x1, y1, x2, y2 = float(x1), float(y1), float(x2), float(y2)
        print ((x1-x2)**2+(y1-y2)**2)**0.5 len(line)>1 len(line) len line 1 x1, y1, x2, y2 = line.strip('\n').split() x1 line.strip('\n').split() line.strip('\n').split line.strip('\n') line.strip line strip '\n' split y1 x2 y2 x1, y1, x2, y2 = float(x1), float(y1), float(x2), float(y2) x1 float(x1) float x1 y1 float(y1) float y1 x2 float(x2) float x2 y2 float(y2) float y2 print ((x1-x2)**2+(y1-y2)**2)**0.5 print ((x1-x2)**2+(y1-y2)**2) print (x1-x2)**2+(y1-y2)**2 (x1-x2)**2 x1-x2 x1 x2 2 (y1-y2)**2 y1-y2 y1 y2 2 0.5 y2 = line.strip('\n').split() line.strip('\n').split() y2 x1, y1, x2, y2 = float(x1), float(y1), float(x2), float(y2) float(x1) x1 x2, y2 = line.strip('\n').split() line.strip('\n').split() x2 y1, x2, y2 = float(x1), float(y1), float(x2), float(y2) float(y1) y1 x1, y1, x2, y2 = line.strip('\n').split() line.strip('\n').split() x1 x2, y2 = float(x1), float(y1), float(x2), float(y2) float(x2) x2 y1, x2, y2 = line.strip('\n').split() line.strip('\n').split() y1 y2 = float(x1), float(y1), float(x2), float(y2) float(y2) y2
import sys

for line in sys.stdin:
    if len(line)>1:
        x1, y1, x2, y2 = line.strip('\n').split()
        x1, y1, x2, y2 = float(x1), float(y1), float(x2), float(y2)
        print ((x1-x2)**2+(y1-y2)**2)**0.5